Acute intermittent porphyria
Diagnosis and Testing
Who else in my family should I test for acute intermittent porphyria?
If you or a family member has had a genetic testing for acute intermittent porphyria (AIP) and a mutation was found in the HMBS gene, other blood relatives can be tested. Siblings of a person with AIP have a 50% chance of also having AIP. Children of a person with AIP also have a 50% chance of having AIP. Even though someone in the family has AIP, it doesn't always mean that there will be other people in the family who has it as well.
Acute Intermittent Porphyria. Gene Reviews. (http://www.ncbi.nlm.nih.gov/books/NBK1193)